Timing Question
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Joined: Jun 2004
Posts: 83
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From: NC
Timing Question
1990, L98, Auto, Coupe
When checking the timing where is the ECM harness that is supposed to be removed? If someone would list the proper steps for checking the timing I would greatly appreciate it.
Thanks
When checking the timing where is the ECM harness that is supposed to be removed? If someone would list the proper steps for checking the timing I would greatly appreciate it.
Thanks
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
The steps for checking the timing are relatively easy. Here is what I usually do.
!. Clean off the timing mark indicator (so you can see the numbers) and clean out the "notch" in the vibration damper. I like to put some white paint on the tip of a screwdriver and apply the paint to the timing notch. Wipe off any excess paint with a rag and let the paint dry. This is only done one time on your engine.
2. Get engine to operating temp and shut it off.
3. Unplug the tan wire connector. This is usually located just above the back edge of the driver side valve cover.
4. Slightly loosen the lock down bolt (located at the base of the distributor). This will allow the distributor to be rotated with hand pressure. The distributor should be snug.....but not loose.
5. Attach the timing light (pickup must go to #1 plug wire and the timing light power leads go to battery) to the engine.
6. Start the engine. Note the idle will usually be lower than normal idle.
7. Shoot the light at the timing mark indicator and note how the timing notch aligns with the stationary timing indicator.
8. Rotate the distributor (it should be snug but not loose from step 4) until the notch aligns with the desired timing setting. You will note that the timing notch will travel in one direction as you move the distributor clockwise and it will move in reverse as the distributor is moved counter-clockwise.
9. After the proper position of the distributor is selected, very carefully tighten the distributor lock down nut without disturbing the position of the distributor.
10. Restart the engine and recheck the timing to verify it has not moved as you tightened the bolt. Shut off the engine.
11. Remove the timing light, reconnect the tan connector from step #3.
12. Remove the negative battery lead for about a minute and reconnect it. This removes the fault code in the ECM.
Sounds long, but it is a simple procedure. You asked for details.....and here they are
SAM
!. Clean off the timing mark indicator (so you can see the numbers) and clean out the "notch" in the vibration damper. I like to put some white paint on the tip of a screwdriver and apply the paint to the timing notch. Wipe off any excess paint with a rag and let the paint dry. This is only done one time on your engine.
2. Get engine to operating temp and shut it off.
3. Unplug the tan wire connector. This is usually located just above the back edge of the driver side valve cover.
4. Slightly loosen the lock down bolt (located at the base of the distributor). This will allow the distributor to be rotated with hand pressure. The distributor should be snug.....but not loose.
5. Attach the timing light (pickup must go to #1 plug wire and the timing light power leads go to battery) to the engine.
6. Start the engine. Note the idle will usually be lower than normal idle.
7. Shoot the light at the timing mark indicator and note how the timing notch aligns with the stationary timing indicator.
8. Rotate the distributor (it should be snug but not loose from step 4) until the notch aligns with the desired timing setting. You will note that the timing notch will travel in one direction as you move the distributor clockwise and it will move in reverse as the distributor is moved counter-clockwise.
9. After the proper position of the distributor is selected, very carefully tighten the distributor lock down nut without disturbing the position of the distributor.
10. Restart the engine and recheck the timing to verify it has not moved as you tightened the bolt. Shut off the engine.
11. Remove the timing light, reconnect the tan connector from step #3.
12. Remove the negative battery lead for about a minute and reconnect it. This removes the fault code in the ECM.
Sounds long, but it is a simple procedure. You asked for details.....and here they are
SAM
Last edited by Sam Lam; Feb 26, 2006 at 01:14 AM.
